Radio route indicators for airplanes



y 29, 1934- J. CHAPMAN 60,297

' RADIO ROUTE INDICATOR FOR AIRPLANES driginal Filed Jl me 20, i929 I NVENTORQ M 6 WW, 9%14 ATTORNEY Patented May 29, 1934 UNITED STATES PATENT OFFICE John Chapman, St. Louis, Mo.

Application June 20, 1929, Serial No. 372,417 Renewed September 8, 1933 2 Claims. (CL 250-11) This invention relates to certain new and useful improvements in radio route indicators for to its destination; secondly, to provide a device' adapted to be actuated by radio waves from a broadcaster at a certain destination, to indicate by different colored lights, such as red and green, whether the plane is on its proper course or diverging from it; thirdly, to indicate how many degrees if any, the plane is off its course; fourthly, to provide a telephone connection to such a device that will keep the pilot in constant communication with his destination; and fifthly, to enable the pilot to know if he should pass over his destination inadvertently, or otherwise.

The accompanying drawing illustrates my invention diagrammatically. The numeral 1 designates an instrument board on which is mounted in plain sight of the pilot, a lamp 2, adapted to show a green light as hereafter described.

At the right of this green light is a lamp 3 and a similar lamp 4 to the left, both adapted to show a red light.

At any convenient point in the fusilage or other place in the air plane, are located loop aerials oi the form having two vertically disposed planes 5 and 6 arranged at right angles to each other; and the medial plane 'I passing through the intersection of said planes 5 and 6, is disposed parallel to the axis 8 of the air plane, or coincident therewith, similar to the compass on a ship.

Therefore when the medial plane of the loops is brought into a direct line with the destination "and the broadcasting station A located there, the air plane will be pointed directly to such destination.

The loop aerial in plane 5 is connected to a radio set 9 by suitable wires as shown, and the loop aerial in plane 6 to another radio set 10 in a similar manner. A battery 11 is wired to an armature 12 of a relay 13 connected by a wire 14 with the radio set 9. A contact 15 of such armature is connected by a wire 16 to said green lamp 2 which has a wire connection 17 with a. contact 18 of a similar armature 19 operating with its relay 20 which has a connecting wire 21 with said radio set 10. Said armature 19 of the relay on the left is wired to said battery 11 511338.! to said armature 12 of the relay on the When the said medial plane '1 (substantially coincident with the air plane axis 8) is pointing directly to the destination, the radio waves from the said broadcaster A will act equally upon the planes 5 and 6 of said loop aerials 4, and send equal impulses through the respective radio sets 9 and 10. From the set 9 the wire 14 will transmit the impulse to the relay l3 and cause the armature 12 to close on the contact 15, thus sending the battery current through the wire 16 to the lamp 2, from which it returns by the wire 17 to the contact 18,and armature 19 connected to said battery 11,--the opposite relay 20 having been energized by a substantially similar impulse to said radio set 10 from the opposite plane 6 of said aerials.

Equal impulses from the planes 5 and 6 through the radio sets 9 and 10 and similarly energized relays 13 and 20, cause the battery 11 to light the green light 2, and continue it burning as long as the air plane is pointed directly to its destination.

Should the air plane swerve from such direct so route, as indicated by dotted lines in the figure, the medial plane 7 would not point to the destination and a stronger impulse from said station would be received by the plane 5 when in the dotted position, due to the more nearly parallel arrangement with regard to said radio waves. A correspondingly weakened impulse is received by the plane 6 in its dotted position. This weakened impulse passing through the radio set 10 and wire 21, would release the armature 19 of the relay 20 and open the battery circuit to i the green lamp, causing it to go out.

On the other hand, the red lamp 3 at the right of the axis will light up as it will receive current from the battery 11 through said wire 16 and a branch wire 22, while the circuit is completed through a wire 23 from said red lamp 3 connected to a contact 24 which is now engaged by said armature 19, and the battery circuit is completed. This red lamp 3 at the right; indi- 1 cates the air plane is oil? its course to the right.

In order to indicate to the pilot the number of degrees he has swerved from the direct course, I provide also a milliammeter or other angle meter 25. The relay 13 has a wire connection 26 to 05 said meter which is connected by a return wire 27 to both the radio sets 9 and 10 as indicated.

The other relay 20 is also connected by a wire 28 to said meter, but when the air plane has swerved to the right as indicated, only the relay 11o 13 will act on said meter and the needle thereon will turn to the right to a corresponding number of degrees.

Thus the pilot will have warning by the red light 3 at the right suddenly burning, and the green lamp going out, that he has swerved from his course, and he will know from the angle meter the number of degrees he is of his course, and thus quickly correct the error or divergence from the direct route to his destination.

Should the air plane swerve in the opposite direction, that is to the left of the direct course, the lamp 4 would burn red under the battery current supplied by the wire 17 and branch wire 17' to said lamp and a return wire 29 connecting the lamp 4 to a binding post contact 30 which will be engaged by the armature 12 under these circumstances, as was the post contact 2& by the opposite relay armature 19 indicated by dotted position.

The number of degrees to the left will be indicated on said meter by the needle moving to I also provide for the pilot being in constantcommunication with his destination by phone, so that he can be advised of storm and other conditions ahead of him. For this purpose I provide head phone receivers 31 and '32 wired to posts 33 and 34 in said return wire 2'7, which is always energized whether the air plane is on its proper course or is swerving to the right or to the left.

When starting, the pilot sets his radio to pick up the radio signals from the station located at his destination. If going beyond said station, he would after arrival, reset his radio to pick up the radio signals on the different. wave length of the further station on his mail, or other route. In this manner he can proceed across the country on the shortest line from station to station, without regard to the visibility enroute.

The pivoted bars forming the armatures 12 and 19 and adapted to engage their corresponding contacts, constitute switches and are actuated by the relays above described or other suitable operative means.

While it is preferred touse the angle meter 25 to corroborate and measure the divergence from the direct course which is indicated at the same time by the red light showing in the lamp 3 or 4, it is evident that such lamps may be used, with the intermediate green light, without such angle meter. However, it is much preferred that such measuring device for the angle of divergence should be used as above described. 7

While I have described my route indicator controlled by radio; as applied to an air plane, it is evident that my device is also useful in connection with ships or other moving man-controlled vehicles,-such as an automobile in the desert,'-and is adapted to indicate the direct route to a broadcaster at the destination, and to give warning of any swerving from said direct route, as above described.

If the pilot should lose his dead reckoning he would know that he was close 'to his destination by the increasing loudness in his head phones, even though he could not see the landing field. If he passed, over his destination the sounds would decrease accordingly. I

Therefore it is evident that should the pilot attempt to navigate by the angle meter alone, cross currents of air acting on the airplane would cause the indicator needle of the angle meter to constantly vary from one to three degrees to the right or left, causing considerable difficulty for the pilot. The meter operates when the plane is only slightly off its course. The relays are adjusted so that they operate the lamps when the plane is three or more degrees off its course. For this reason the lamps are controlled by the relays in such manner that they will operate the red lamps only when the airplane varies three or more degrees from the direct course.

While enroute, the radio sets can be tuned to a transmitter located at the point of departure to enable the pilot to know should he drift off-the course leading from his point of departure to his destination. He can thus check up whether he is on a direct line between said points.

Also the radio sets can be tuned while en route to a third station located to the right or left of his destination, and noting on the angle meter the.

number of degrees said station is to the right or left, will enable the pilot to locate his position on the usual map, and find the distance he has flown or traveled from the point of departure. The anglemeter will constantly vary while the plane is in normal flight but it can be held stationary for a few seconds by properly controlling the plane while the position is being taken.

The automatic operation of the lamps by the relays eliminates the necessity of constantly observing the anglemeter.

Constant communication. is maintained with the station to which he has tuned, without interfering with the navigating devices or requiring a separate frequency for this purpose as used by the beacon system now in practice, which navigates on 285 kilocycles and communicates on 333 kilocycles.

By noting the position of the plane on his route, the pilot is able to determine when he approaches his destination.

No interference can be caused by static or the engine ignition system, because of the fact that equal intensities of current would be induced to both radio sets through their respective loops, neutralizing the current in relays 13 and 20 and anglemeter 25 caused by said static or ignition. Should the stations to which the radio sets are tuned stop transmitting for any reason, the radio sets would release both relays and their respective armatures, causing all three lamps to light and the anglemeter to remain stationary at zero, thus notifying the pilot of the fact. Or if for any reason one of the radio sets should cease to function, the anglemeter would turn to a maximum of 45 degreesto the right of left and remain stationary, regardless of the movement of the plane.

In using both lamps and anglemeter for navigating, the danger of becoming lost through failure to observe the anglemeter at all times because of preoccupation of the pilot is avoided by the automatic flashing of a red light should theplane drift to the right or left of the course;

Constant communication is maintained with the stations to which the radio sets are tuned,

by the head phones which are connected in the manner described so that a change in signal strength in either of the two radio sets. will cause no corresponding change in the head phones.

My construction accomplishes efllciently three cooperating things: first, to indicate a direct course between two points on the earths surface; second, to indicate the deviation from said course and to enable the pilot to determine his posi tion and distance between two points; and third, to enable him to maintain constant communication with the station to which he is tuned without interference with the indicating devices or to require a separate frequence for this purpose.

I claim:

1, A route indicator for airplanes comprising two radio receiving sets, fixed loop aerials extending at right angles to each other each connected to one of said receiving sets, a pair of relays each controlled by one of said receiving sets, a source of electrical energy connected in series between the armatures of said relays, a signal light connected in series with said source of electrical energy, means for illuminating said light when said relays are simultaneously energized, a pair of warning lights, means for connecting said warning lights with said source of electrical energy through the relay arrnatures when either one of said relays is deenergized, an angle meter connected in series with said relays and with said receiving sets and having a common return wire constantly energized by said receiving sets, Whereby the signal lights will indicate whether or not the airplane is on its course, and if ofi its course, the angle meter will indicate the degree of va riation of error.

2. The combination as set forth in claim 1, and a set of head phones connected in series with the constantly energized return wire whereby signals from a transmitting station can be received at all times during the operation of the route indicator apparatus.

JOHN CHAPMAN. 

